State-owned telecom giant VNPT said it has submitted to the government a plan to divest its stake from one of its mobile phone subsidiaries, Vinaphone or MobiFone, according to news website VnExpress.

The move comes on the heels of a new regulation on ownership in telecom firms taking effect June 1. The regulation stipulates that an investor holding more than a 20 percent stake in one telecom firm cannot own more than a 20 percent stake in another.

VNPT, as Vietnam Posts and Telecommunications Group is known, now owns both Vinaphone and MobiFone.

To avoid violating the new rule, VNPT plans to sell shares of either of the two mobile networks. The group is also considering two other options: merging the two firms or selling shares of the group as a whole.

VnExpress cited VNPT Deputy General Director as saying that the company has not made its final decision yet and is awaiting instructions from the authorities.

Market analysts have said the group is caught in a dilemma because both Vinaphone and MobiFone are too lucrative to give up. The latter in particular contributes half the profit that VNPT earns.

They also said merging the two networks would create a giant mobile phone company that could hurt competition in the market.

Pham Hong Hai, director of the Telecommunications Department under the Ministry of Information and Communications, told VnExpress that it would take a long time to either sell shares of the companies or merge them. "I can't tell how long because a final decision can't be made in just a month or two. But the process must not go on for years."

The sale of shares in MobiFone had been scheduled for the second quarter of 2009, but has been delayed since.